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Bats are natural reservoir hosts of many important zoonotic viruses but because there are few immunological reagents and breeding colonies available for infectious disease research, little is known about their immune responses to infection. We established a breeding colony Jamaican fruit bats ( Artibeus jamaicensis ) to study bat virology and immunology. The species is used as a natural reservoir model for H18N11 influenza A virus, and as a surrogate model for SARS-CoV-2, MERS-CoV and Tacaribe virus. As part of our ongoing efforts to develop this model organism, we sought to identify commercially available monoclonal antibodies (mAb) for profiling Jamaican fruit bat lymphocytes. We identified several cross-reactive mAb that can be used to identify T and B cells; however, we were unable to identify mAb for three informative T cell markers, CD3γ, CD4 and CD8α. We targeted these markers for the generation of hybridomas, and identified several clones to each that can be used with flow cytometry and fluorescence microscopy. Specificity of the monoclonal antibodies was validated by sorting lymphocytes, followed by PCR identification of confirmatory transcripts. Spleens of Jamaican fruit bats possess about half the number of T cells than do human or mouse spleens, and we identified an unusual population of cells that expressed the B cell marker CD19 and the T cell marker CD3. The availability of these monoclonal antibodies will permit a more thorough examination of adaptive immune responses in Jamaican fruit bats that should help clarify how the bats control viral infections and without disease. Importance: Bats naturally host a number of viruses without disease, but which can cause significant disease in humans. Virtually nothing is known about adaptive immune responses in bats because of a lack of immunological tools to examine such responses. We have begun to address this deficiency by identifying several commercially available monoclonal antibodies to human and mouse antigens that are cross-reactive to Jamaican fruit bat lymphocyte orthologs. We also generated monoclonal antibodies to Jamaican fruit bat CD3γ, CD4 and CD8α that are suitable for identifying T cell subsets by flow cytometry and immunofluorescent staining of fixed tissues. Together, these reagents will allow a more detailed examination of lymphocyte populations in Jamaican fruit bats.
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Bacille Calmette-Guerin (BCG) is the only licensed vaccine against Mycobacterium tuberculosis (Mtb), the causative agent of tuberculosis (TB) disease. However, BCG has limited efficacy, necessitating the development of better vaccines. Non-tuberculous mycobacteria (NTMs) are opportunistic pathogens present ubiquitously in the environment. TB endemic countries experience higher exposure to NTMs, but previous studies have not elucidated the relationship between NTM exposure and BCG efficacy against TB. Therefore, we develop a mouse model (BCG + NTM) to simulate human BCG immunization regime and continuous NTM exposure. BCG + NTM mice exhibit superior and prolonged protection against pulmonary TB, with increased B cell influx and anti-Mtb antibodies in serum and airways, compared with BCG alone. Notably, spatial transcriptomics and immunohistochemistry reveal that BCG + NTM mice formed B cell aggregates with features of germinal center development, which correlate with reduced Mtb burden. Our studies suggest a direct relationship between NTM exposure and TB protection, with B cells playing a crucial role.
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Mycobacterium tuberculosis , Tuberculosis Pulmonar , Tuberculosis , Ratones , Humanos , Animales , Vacuna BCG , Micobacterias no Tuberculosas , Inmunidad CelularRESUMEN
The objective of this study was to characterize the effect of Bacillus Calmette-Guérin (BCG) vaccination and M. tuberculosis infection on gut and lung microbiota of C57BL/6 mice, a well-characterized mouse model of tuberculosis. BCG vaccination and infection with M. tuberculosis altered the relative abundance of Firmicutes and Bacteroidetes phyla in the lung compared with control group. Vaccination and infection changed the alpha- and beta-diversity in both the gut and the lung. However, lung diversity was the most affected organ after BCG vaccination and M. tuberculosis infection. Focusing on the gut-lung axis, a multivariate regression approach was used to compare profile evolution of gut and lung microbiota. More genera have modified relative abundances associated with BCG vaccination status at gut level compared with lung. Conversely, genera with modified relative abundances associated with M. tuberculosis infection were numerous at lung level. These results indicated that the host local response against infection impacted the whole microbial flora, while the immune response after vaccination modified mainly the gut microbiota. This study showed that a subcutaneous vaccination with a live attenuated microorganism induced both gut and lung dysbiosis that may play a key role in the immunopathogenesis of tuberculosis. IMPORTANCE The microbial communities in gut and lung are important players that may modulate the immunity against tuberculosis or other infections as well as impact the vaccine efficacy. We discovered that vaccination through the subcutaneous route affect the composition of gut and lung bacteria, and this might influence susceptibility and defense mechanisms against tuberculosis. Through these studies, we can identify microbial communities that can be manipulated to improve vaccine response and develop treatment adjuvants.
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Microbioma Gastrointestinal , Mycobacterium bovis , Mycobacterium tuberculosis , Tuberculosis , Animales , Vacuna BCG , Pulmón , Ratones , Ratones Endogámicos C57BL , Tuberculosis/microbiología , VacunaciónRESUMEN
Guinea pigs have been used as a model for Mycobacterium tuberculosis infection for many years and have been more recently adopted as a model for testing new tuberculosis (TB) vaccines. From the time of Robert Koch, who used guinea pigs to test theories about the newly discovered pathogen, the guinea pig has modeled active human infections, as it is susceptible to infection with low numbers of organisms. This article describes the modern use of the guinea pig to examine the pathology of the disease and the protocols used to examine specific outcomes associated with aerosol infection with virulent M. tuberculosis. The guinea pig is used extensively to investigate the ability of new TB vaccines to reduce TB disease, and two models have been employed. The first is the long-term disease model, in which vaccinated guinea pigs are monitored for disease after infection, and the second is the short-term assessment of mycobacterial burden model, which can determine the ability of a vaccine to reduce organism burden. © 2021 Wiley Periodicals LLC. Basic Protocol 1: Preparation of virulent Mycobacterium tuberculosis seed stocks for animal infections Basic Protocol 2: Preparation of virulent Mycobacterium tuberculosis working stocks for animal infections Basic Protocol 3: Preparation of M. tuberculosis for aerosol infection of guinea pigs Basic Protocol 4: Injection of guinea pigs Basic Protocol 5: Blood collection from live guinea pigs Basic Protocol 6: Guinea pig euthanasia.
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Mycobacterium tuberculosis , Vacunas contra la Tuberculosis , Tuberculosis , Animales , Modelos Animales de Enfermedad , Cobayas , Tuberculosis/prevención & controlRESUMEN
A single intradermal vaccination with an antibiotic-less version of BCGΔBCG1419c given to guinea pigs conferred a significant improvement in outcome following a low dose aerosol exposure to M. tuberculosis compared to that provided by a single dose of BCG Pasteur. BCGΔBCG1419c was more attenuated than BCG in murine macrophages, athymic, BALB/c, and C57BL/6 mice. In guinea pigs, BCGΔBCG1419c was at least as attenuated as BCG and induced similar dermal reactivity to that of BCG. Vaccination of guinea pigs with BCGΔBCG1419c resulted in increased anti-PPD IgG compared with those receiving BCG. Guinea pigs vaccinated with BCGΔBCG1419c showed a significant reduction of M. tuberculosis replication in lungs and spleens compared with BCG, as well as a significant reduction of pulmonary and extrapulmonary tuberculosis (TB) pathology measured using pathology scores recorded at necropsy. Evaluation of cytokines produced in lungs of infected guinea pigs showed that BCGΔBCG1419c significantly reduced TNF-α and IL-17 compared with BCG-vaccinated animals, with no changes in IL-10. This work demonstrates a significantly improved protection against pulmonary and extrapulmonary TB provided by BCGΔBCG1419c in susceptible guinea pigs together with an increased safety compared with BCG in several models. These results support the continued development of BCGΔBCG1419c as an effective vaccine for TB.
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Vacuna BCG/administración & dosificación , Mycobacterium tuberculosis/aislamiento & purificación , Tuberculosis/prevención & control , Vacunación/métodos , Animales , Vacuna BCG/efectos adversos , Vacuna BCG/inmunología , Modelos Animales de Enfermedad , Femenino , Cobayas , Humanos , Inmunogenicidad Vacunal , Inyecciones Intradérmicas , Pulmón/inmunología , Pulmón/microbiología , Ratones , Mycobacterium tuberculosis/inmunología , Células RAW 264.7 , Tuberculosis/diagnóstico , Tuberculosis/inmunología , Tuberculosis/microbiologíaRESUMEN
Toll-Like Receptor (TLR) 9 stimulation is required for induction of potent immune responses against pathogen invasion. The use of unmethylated CpG as adjuvants in vaccines provides an excellent means of stimulating adaptive immunity. Our data demonstrate that CpG-C provided prolonged immune responses in the mouse model of tuberculosis when formulated with liposomes and the Mycobacterium tuberculosis antigen ESAT-6. A reduction in the mycobacterial burden was best achieved when administered as an intranasal vaccine and was dependent on type I interferon (IFN). There was a significant difference between CpG-C inoculated wild type and IFN-αR1-/- mice, indicating that type I IFN plays a role in the immune response following CpG-C inoculation. Further analysis showed that early NK cell presence was not an absolute requirement, although elevated IFN-γ levels were detected in the lungs of mice within 48 h. The reduction in mycobacterial burden was MyD88-independent as CpG-C inoculated MyD88-/- mice showed comparable mycobacterial burdens to wild type mice with no detriment due to the lack of MyD88. Together our data show that pulmonary stimulation of TLR9 bearing antigen presenting cells resulted in the induction of protective immunity against M. tuberculosis infection that was dependent on type I IFN signaling.
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Adyuvantes Inmunológicos/administración & dosificación , Antígenos Bacterianos/administración & dosificación , Proteínas Bacterianas/administración & dosificación , Inmunidad Mucosa/efectos de los fármacos , Pulmón/efectos de los fármacos , Mycobacterium tuberculosis/efectos de los fármacos , Oligodesoxirribonucleótidos/administración & dosificación , Mucosa Respiratoria/efectos de los fármacos , Vacunas contra la Tuberculosis/administración & dosificación , Tuberculosis Pulmonar/prevención & control , Adyuvantes Inmunológicos/efectos adversos , Administración Intranasal , Animales , Células Cultivadas , Modelos Animales de Enfermedad , Femenino , Interacciones Huésped-Patógeno , Interferón gamma/metabolismo , Pulmón/inmunología , Pulmón/metabolismo , Pulmón/microbiología , Ratones Endogámicos C57BL , Ratones Noqueados , Mycobacterium tuberculosis/inmunología , Mycobacterium tuberculosis/patogenicidad , Factor 88 de Diferenciación Mieloide/genética , Factor 88 de Diferenciación Mieloide/metabolismo , Rociadores Nasales , Receptor de Interferón alfa y beta/genética , Receptor de Interferón alfa y beta/metabolismo , Mucosa Respiratoria/inmunología , Mucosa Respiratoria/metabolismo , Mucosa Respiratoria/microbiología , Transducción de Señal , Receptor Toll-Like 9/agonistas , Receptor Toll-Like 9/metabolismo , Tuberculosis Pulmonar/inmunología , Tuberculosis Pulmonar/metabolismo , Tuberculosis Pulmonar/microbiologíaRESUMEN
The live attenuated Mycobacterium bovis strain, Bacille Calmette Guérin (BCG) is a potent innate immune stimulator. In the C57BL/6 mouse model of tuberculosis, BCG vaccination leads to a significant reduction of Mycobacterium tuberculosis burden after aerogenic infection. Our studies indicated that BCG induced protection against pulmonary tuberculosis was independent of T cells and present as early as 7 days after vaccination. This protection showed longevity, as it did not wane when conventional T cell and TNF-α deficient mice were infected 30 days post-vaccination. As BCG induced mycobacterial killing after 7 days, this study investigated the contributions of the innate immune system after BCG vaccination to better understand mechanisms required for mycobacterial killing. Subcutaneous BCG inoculation resulted in significant CD11b+F4/80+ monocyte subset recruitment into the lungs within 7 days. Further studies revealed that killing of mycobacteria was dependent on the viability of BCG, because irradiated BCG did not have the same effect. Although others have identified BCG as a facilitator of trained innate immunity, we found that BCG reduced the mycobacterial burden in the absence of mechanisms required for trained innate immunity, highlighting a role for macrophages and neutrophils for vaccine induced killing of M. tuberculosis.
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Vacuna BCG/inmunología , Inmunidad Innata/inmunología , Macrófagos/inmunología , Mycobacterium tuberculosis/inmunología , Neutrófilos/inmunología , Animales , Ratones , Ratones Endogámicos C57BL , Tuberculosis/inmunologíaRESUMEN
The guinea pig model of tuberculosis is used extensively to assess the efficacy of novel tuberculosis vaccines. There are established parameters to determine vaccine efficacy in this model, but the science community currently lacks established biomarkers for early detection and monitoring of experimental disease in guinea pigs. To define a set of biomarkers that could be used as benchmarks for disease progression and early endpoint criteria, we assessed serum biochemical and hematology parameters in 2 groups of guinea pigs-one vaccinated with the attenuated Mycobacterium bovis vaccine strain (BCG) and one sham-vaccinated with saline-and then experimentally infected with a virulent strain of Mycobacterium tuberculosis. After infection, WBC showed the strongest differences between saline-inoculated and vaccinated animals, with more subtle changes in other serum biochemical parameters, including ALT and ALP. Therefore, this study provides a starting point for evaluating the utility of blood values as possible early endpoint criteria in the guinea pig model of tuberculosis.
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Determinación de Punto Final/métodos , Cobayas , Vacunas contra la Tuberculosis/inmunología , Animales , Biomarcadores/sangre , Modelos Animales de Enfermedad , Progresión de la Enfermedad , Femenino , Mycobacterium tuberculosis/inmunologíaRESUMEN
Pharmacokinetic/pharmacodynamic studies of anti-tuberculosis agents in animal models of tuberculosis are hampered by the frequent necessity to perform sample bioanalysis outside the biosafety level-3 environment. Thus, each specimen has to undergo tedious and time-consuming sample sterilization procedures that may also affect drug stability. Here, we tested treatment of Mycobacterium tuberculosis (Mtb) infected samples with methanol to sterilize samples while preserving drug integrity for further pharmacokinetic/pharmacodynamic evaluations. Tissue samples harvested from Mtb infected mice were homogenized, incubated in methanol, and tested for sterility. Once sterility was confirmed, the samples were used to determine concentrations of the anti-tuberculosis drug spectinamide-1599 in lung homogenates using liquid chromatography coupled with mass spectrometry. The results demonstrate that methanol sterilizes tissue samples harvested from Mtb infected mice without altering the integrity of the drug in the tissue.
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Antituberculosos/farmacología , Metanol/farmacología , Mycobacterium tuberculosis/efectos de los fármacos , Manejo de Especímenes/métodos , Esterilización/métodos , Tuberculosis/microbiología , Animales , Antituberculosos/análisis , Recuento de Colonia Microbiana , Estudios de Factibilidad , Femenino , Infección de Laboratorio/prevención & control , Pulmón/microbiología , Ratones Endogámicos BALB C , Pruebas de Sensibilidad Microbiana/métodos , Viabilidad Microbiana/efectos de los fármacos , Mycobacterium tuberculosis/fisiología , Espectinomicina/análogos & derivados , Espectinomicina/análisis , Espectinomicina/farmacología , Células Madre/efectos de los fármacosRESUMEN
Mycobacterium tuberculosis (M. tuberculosis), the causative agent of human tuberculosis (TB), is estimated to be harbored by up to 2 billion people in a latent TB infection (LTBI) state. The only TB vaccine approved for use in humans, BCG, does not confer protection against establishment of or reactivation from LTBI, so new vaccine candidates are needed to specifically address this need. Following the hypothesis that mycobacterial biofilms resemble aspects of LTBI, we modified BCG by deleting the BCG1419c gene to create the BCGΔBCG1419c vaccine strain. In this study, we compared cytokine profiles, bacterial burden, and lung lesions after immunization with BCG or BCGΔBCG1419c before and after 6 months of aerosol infection with M. tuberculosis H37Rv in the resistant C57BL/6 mouse model. Our results show that in infected mice, BCGΔBCG1419c significantly reduced lung lesions and IL-6 in comparison to the unmodified BCG strain, and was the only vaccine that decreased production of TNF-α and IL-10 compared to non-vaccinated mice, while vaccination with BCG or BCGΔBCG1419c significantly reduced IFN-γ production. Moreover, transcriptome profiling of BCGΔBCG1419c suggests that compared to BCG, it has decreased expression of genes involved in mycolic acids (MAs) metabolism, and antigenic chaperones, which might be involved in reduced pathology compared to BCG-vaccinated mice.
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With more than 9 million new infections and 1.5 million deaths claimed every year, tuberculosis remains one of the major scourges of humankind. The only vaccine available against this disease, the attenuated strain Mycobacterium bovis, BCG is effective against severe forms of the disease in infants, but scarcely effective in protecting adults from the pulmonary form of the disease, thus not stopping transmission. Consequently, the development of an effective anti-tuberculosis vaccine is a major goal for improving global health. The most common concept is that a more effective vaccine should include a first immunization with a live vaccine followed by the administration of an acellular boosting vaccine. In this approach, the live vaccine might be either BCG or a different, more efficient attenuated strain. Recently, we showed that a Mycobacterium tuberculosis mutant missing the gene encoding for the extracellular function sigma factor SigE, is strongly attenuated and is able to induce a more effective protection from M. tuberculosis infection compared to BCG in mice. We now further characterize the protective potential of this novel strain in the guinea pig model of tuberculosis. In the guinea pig, it had limited growth but induced a Th1 immune response and was able to significantly reduce the number of colony forming units as well as prolong survival. Taken together these data provide evidence for the use of the M. tuberculosis sigE mutant as the basis for further development as a vaccine against infection.
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Proteínas Bacterianas/inmunología , Pulmón/inmunología , Mutación , Mycobacterium tuberculosis/inmunología , Factor sigma/inmunología , Vacunas contra la Tuberculosis/administración & dosificación , Tuberculosis Pulmonar/prevención & control , Vacunas Atenuadas/administración & dosificación , Animales , Proteínas Bacterianas/genética , Citocinas/inmunología , Citocinas/metabolismo , Modelos Animales de Enfermedad , Cobayas , Interacciones Huésped-Patógeno , Pulmón/metabolismo , Pulmón/microbiología , Mycobacterium tuberculosis/genética , Mycobacterium tuberculosis/crecimiento & desarrollo , Factor sigma/genética , Células TH1/inmunología , Células TH1/metabolismo , Células TH1/microbiología , Factores de Tiempo , Vacunas contra la Tuberculosis/genética , Vacunas contra la Tuberculosis/inmunología , Tuberculosis Pulmonar/inmunología , Tuberculosis Pulmonar/metabolismo , Tuberculosis Pulmonar/microbiología , Vacunas Atenuadas/genética , Vacunas Atenuadas/inmunologíaRESUMEN
The humanized mouse model has been developed as a model to identify and characterize human immune responses to human pathogens and has been used to better identify vaccine candidates. In the current studies, the humanized mouse was used to determine the ability of a vaccine to affect the immune response to infection with Mycobacterium tuberculosis. Both human CD4+ and CD8+ T cells responded to infection in humanized mice as a result of infection. In humanized mice vaccinated with either BCG or with CpG-C, a liposome-based formulation containing the M. tuberculosis antigen ESAT-6, both CD4 and CD8 T cells secreted cytokines that are known to be required for induction of protective immunity. In comparison to the C57BL/6 mouse model and Hartley guinea pig model of tuberculosis, data obtained from humanized mice complemented the data observed in the former models and provided further evidence that a vaccine can induce a human T-cell response. Humanized mice provide a crucial pre-clinical platform for evaluating human T-cell immune responses in vaccine development against M. tuberculosis.
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Vacuna BCG/administración & dosificación , Linfocitos T CD4-Positivos/efectos de los fármacos , Linfocitos T CD8-positivos/efectos de los fármacos , Pulmón/efectos de los fármacos , Mycobacterium tuberculosis/inmunología , Oligodesoxirribonucleótidos/administración & dosificación , Tuberculosis Pulmonar/prevención & control , Animales , Vacuna BCG/inmunología , Linfocitos T CD4-Positivos/inmunología , Linfocitos T CD4-Positivos/metabolismo , Linfocitos T CD4-Positivos/microbiología , Linfocitos T CD8-positivos/inmunología , Linfocitos T CD8-positivos/metabolismo , Linfocitos T CD8-positivos/microbiología , Citocinas/inmunología , Citocinas/metabolismo , Modelos Animales de Enfermedad , Femenino , Cobayas , Humanos , Antígenos Comunes de Leucocito/sangre , Antígenos Comunes de Leucocito/inmunología , Pulmón/inmunología , Pulmón/metabolismo , Pulmón/microbiología , Trasplante de Células Madre Mesenquimatosas , Ratones , Ratones Endogámicos C57BL , Ratones Endogámicos NOD , Ratones SCID , Mycobacterium tuberculosis/metabolismo , Oligodesoxirribonucleótidos/inmunología , Fenotipo , Tuberculosis Pulmonar/sangre , Tuberculosis Pulmonar/inmunología , Tuberculosis Pulmonar/microbiología , VacunaciónRESUMEN
In the last decade, there were 10 million new tuberculosis cases per year globally. Around 9.5% of these cases were caused by isoniazid resistant (INHr) Mycobacterium tuberculosis (Mtb) strains. Although isoniazid resistance in Mtb is multigenic, mutations in the catalase-peroxidase (katG) gene predominate among the INHr strains. The effect of these drug-resistance-conferring mutations on Mtb fitness and virulence is variable. Here, we assessed differences in bacterial growth, immune response and pathology induced by Mtb strains harboring mutations at the N-terminus of the katG gene. We studied one laboratory and one clinically isolated Mtb clonal pair from different genetic lineages. The INHr strain in each pair had one and two katG mutations with significantly reduced levels of the enzyme and peroxidase activity. Both strains share the V1A mutation, while the double mutant clinical INHr had also the novel E3V katG mutation. Four groups of C57BL/6 mice were infected with one of the Mtb strains previously described. We observed a strong reduction in virulence (reduced bacterial growth), lower induction of proinflammatory cytokines and significantly reduced pathology scores in mice infected with the clinical INHr strain compared to the infection caused by its INHs progenitor strain. On the other hand, there was a subtle reduction of bacteria growth without differences in the pathology scores in mice infected with the laboratory INHr strain. Our results also showed distinct alkyl-hydroperoxidase C (AhpC) levels in the katG mutant strains, which could explain the difference in the virulence profile observed. The difference in the AhpC levels between clonal strains was not related to a genetic defect in the gene or its promoter. Cumulatively, our results indicate that the virulence, pathology and fitness of INHr strains could be negatively affected by multiple mutations in katG, lack of the peroxidase activity and reduced AhpC levels.
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Proteínas Bacterianas/genética , Catalasa/genética , Farmacorresistencia Bacteriana/genética , Isoniazida/farmacología , Mycobacterium tuberculosis/efectos de los fármacos , Mycobacterium tuberculosis/patogenicidad , Animales , Antituberculosos/farmacología , Proteínas Bacterianas/metabolismo , Catalasa/metabolismo , Citocinas/metabolismo , Farmacorresistencia Bacteriana/efectos de los fármacos , Femenino , Pulmón/microbiología , Pulmón/patología , Ratones Endogámicos C57BL , Mutación , Mycobacterium tuberculosis/genética , Peroxidasas/genética , Peroxidasas/metabolismo , Tuberculosis/microbiología , Tuberculosis/patologíaRESUMEN
Over the last 10 years, Mycobacterium abscessus group strains have emerged as important human pathogens, which are associated with significantly higher fatality rates than any other rapidly growing mycobacteria. These opportunistic pathogens are widespread in the environment and can cause a wide range of clinical diseases, including skin, soft tissue, central nervous system, and disseminated infections; by far, the most difficult to treat is the pulmonary form. Infections with M. abscessus are often multidrug-resistant (MDR) and require prolonged treatment with various regimens and, many times, result in high mortality despite maximal therapy. We report here the evaluation of diverse mouse infection models for their ability to produce a progressive high level of infection with M. abscessus. The nude (nu/nu), SCID (severe combined immunodeficiency), gamma interferon knockout (GKO), and granulocyte-macrophage colony-stimulating factor (GMCSF) knockout mice fulfilled the criteria for an optimal model for compound screening. Thus, we set out to assess the antimycobacterial activity of clarithromycin, clofazimine, bedaquiline, and clofazimine-bedaquiline combinations against M. abscessus-infected GKO and SCID murine infection models. Treatment of GKO and SCID mice with a combination of clofazimine and bedaquiline was the most effective in decreasing the M. abscessus organ burden.
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Antibacterianos/farmacología , Factor Estimulante de Colonias de Granulocitos y Macrófagos/metabolismo , Mycobacterium/efectos de los fármacos , Animales , Claritromicina/farmacología , Clofazimina/farmacología , Diarilquinolinas/farmacología , Factor Estimulante de Colonias de Granulocitos y Macrófagos/genética , Ratones , Ratones Noqueados , Ratones SCID , Pruebas de Sensibilidad Microbiana , Infecciones por MycobacteriumRESUMEN
The global epidemic caused by the bacterial pathogen Mycobacterium tuberculosis continues unabated. Moreover, the only available vaccine against tuberculosis, Mycobacterium bovis bacillus Calmette-Guérin (BCG), demonstrates variable efficacy. To respond to this global threat, new animal models that mimic the pathological disease process in humans are required for vaccine testing. One new model, susceptible C3Heb/FeJ mice, is similar to human tuberculosis in that these animals are capable of forming necrotic tubercle granulomas, in contrast to resistant C3H/HeOuJ mice. In this study, we evaluated the impact of prior BCG vaccination of C3Heb/FeJ and C3H/HeOuJ mice on exposure to a low-dose aerosol of Mycobacterium tuberculosis W-Beijing strain SA161. Both BCG-vaccinated murine strains demonstrated reduced bacterial loads 25 days after infection compared to controls, indicating vaccine efficacy. However, during chronic infection, vaccine efficacy waned in C3H/HeOuJ but not in C3Heb/FeJ mice. Protection in vaccinated C3Heb/FeJ mice was associated with reduced numbers of CD11b(+) Gr1(+) cells, increased numbers of effector and memory T cells, and an absence of necrotic granulomas. BCG vaccine efficacy waned in C3H/HeOuJ mice, as indicated by reduced expression of gamma interferon (IFN-γ) and increased expressions of interleukin-17 (IL-17), IL-10, and Foxp3 by T cells compared to C3Heb/FeJ mice. This is the first murine vaccine model system described to date that can be utilized to dissect differential vaccine-derived immune efficacy.